Studies On The Temporal And Spatial Changes Of Desertification In Horqin Sandy Land During The Recent 100 Years

Desertification is a threat to human survival and sustainable development ,so it is a major environmental and social-economic issue, and is a focus of global attention, desertification research has become a hot issue of the current academic concerns. Horqin Sandy Land located in the eastern section of the Farming-pastoral Zone of Northern China, and is a typical fragile ecological environment and a sensitive area.Therefore,so it is a typical area in the development of Chinese desertification. Kerqinzuoyihouqi Banner located in the hinterland of Horqin Sandy Land, and distributes throughout the area in Horqin Sandy Land,and is a major component of the Horqin Sandy Land.It is situated at the Horqin Sandy Land center,and the entire boundary distributes in the Horqin sand scope,and it is the Horqin sand important constituent. With the population immigration and the development of reclamation during recent 100 years,the fixed dune of the study area activated, the sand spreaded, desertification strongly developed,so it is a typical desertification area, and the process of desertification is quite representative.Based on field observations and previous studies, taking modern historical literature, topographic map(1935), Horqin sandy Land desertification status map(1975), Landsat TM image data(2000/2005) as the main information sources, firstly in support of the image processing software Arcview3.2 GIS, four vector deserty data was obtained, and then an Spatial overlay analysis of four data was carried on to establish a GIS database of land desertification during nearly 100 years. Secondly, relied on the database the prent desertification present situation was analysed. and the time and space characteristics of desertification changes in nearly 100 years can be found out. Finally, the main driving factors of land desertification is fully discussed,and Horqin sandy anti-desertification measures was proposed.The findings indicated that: the desertification present situation in 2005 is in its optimum condition during the past 50 years. Desertified land takes up 35% of the total area, and approximately 43% of the desertified land is slightly desertified.Desertified land mainly distributes in the west;desertification continue to develop in the recent 100 years. The desertification development process has experienced intense development(1935-1975)-reversal(1975-2000)-stability(2000-2005).Although the desertification state in 2005 approached the state in 1935, there still are 19% desertification land compared with that in 1935; Spatial distribution changes in the past century is that the developed desertified land mainly distributes in southwestern and north , and the reversal desertification land distributes in the east and northwest; Analysis of the affecting factors of the development of land desertification indicate that the human factor is the main reason of desertification such as rapid population growth and looting of land,overgrazing,excessive cutting and other predatory exploitation and misconducted economic activities. In response, the Horqin sandy land desertification prevention and control measures has been proposed as following: control population growth,reduce the pressure on natural resources and ecological environment.